Low profile connection for pressure containment devices

ABSTRACT

An annular blowout preventer (BOP). The annular BOP includes an annular housing having a base. The base includes a plurality of fasteners extending from an interior of the housing to an exterior of the housing via fastener holes formed through the connector base. The annular BOP further includes a seal plate positioned at least partially adjacent interior ends of the plurality of fastener. The annular BOP further includes an annular elastomeric element positioned within the interior of the housing and an annular piston positioned within the interior of the housing. The piston, when driven towards the elastomeric element, deforms the elastomeric element and forces the elastomeric element to constrict radially inward.

BACKGROUND OF THE INVENTION 1. Technical Field

Embodiments of the subject matter disclosed herein generally relate tosubsea oil and gas pressure containment equipment. More particularly,the present technology relates to annular blowout preventors.

2. Discussion of the Background

A blowout preventer assembly is employed for offshore well drillingoperations. The blowout preventer assembly includes a blowout preventerstack (BOP stack) that includes several ram preventers. The BOP stacklands on and connects to a wellhead housing either on the surface or onthe sea floor. A surface BOP stack is configured with an annular BOPconnected to several ram BOPs below with a connector on bottom thatconnects to a wellhead or high pressure housing. A subsea stack isconfigured with a lower marine riser package (LMRP) configured with oneor two annular BOPs that connect to a tubular mandrel on the upper endof the lower BOP stack, which is configured with multiple ram BOPs witha connector on bottom for connecting to a subsea wellhead. The LMRPsecures to a lower end of the riser and has control pods that controlvarious functions of the BOP stack and LMRP. The LMRP also has one ormore annular blowout preventers, which can seal around pipe of a varietyof sizes as well as completely close the passage.

Both surface stacks and subsea stacks are large pieces of equipment, andare quite tall. It would be desirable to reduce the overall height andweight of the BOP assembly because of height restrictions when theequipment is stowed on the rig. A reduced height would allow the use ofthe equipment on rigs with a lower deck height and reduce the center ofgravity and overall bending moment on a subsea wellhead. A reducedheight and weight would allow for smaller rig designs or allow existingrigs to increase their operational limits. It would also allow for theinstallation of an additional ram BOP preventer in the BOP stack withoutadding the full height of the additional ram to the assembled BOP stackand LMRP. More generally, a reduced height annular BOP may be desirablefor these and other reasons.

SUMMARY OF THE INVENTION

One embodiment of the present technology provides an annular blowoutpreventer (BOP). The annular BOP includes an annular housing having abase. The base includes a plurality of fasteners extending from aninterior of the housing to an exterior of the housing via fastener holesformed through the connector base. The annular BOP further includes aseal plate positioned at least partially adjacent interior ends of theplurality of fastener. The annular BOP further includes an annularelastomeric element positioned within the interior of the housing and anannular piston positioned within the interior of the housing. Thepiston, when driven towards the elastomeric element, deforms theelastomeric element and forces the elastomeric element to constrictradially inward.

Another embodiment of the present technology provides subsea systemwhich includes a riser coupled to a vessel, a lower marine riser packagecoupled to the riser opposite the vessel, and an annular blowoutpreventer (BOP) coupled to the lower marine riser package. The BOPincludes an annular housing having a base. The base includes a pluralityof fasteners extending from an interior of the housing to an exterior ofthe housing via fastener holes formed through the base. The annular BOPalso includes a seal plate positioned at least partially adjacentinterior ends of the plurality of fasteners, an annular elastomericelement positioned within the interior of the housing, and an annularpiston positioned within the interior of the housing. The piston, whendriven towards the elastomeric element, deforms the elastomeric elementand forces the elastomeric element to constrict radially inward. Thesubsea system further includes one or more ram BOPs coupled to theannular BOP.

Another embodiment of the present technology provides a method ofinstalling an annular blowout preventer (BOP). The method includesplacing a body of a housing of the annular BOP onto a ram BOP or subseaequipment, wherein the body has a base with a plurality of fastenerholes formed therethrough. The method further includes securing the bodyto a ram BOP or the subsea equipment with a plurality of fastenersinserted through the plurality of fastener holes. The plurality offastener holes is sealed off from the wellbore and hydraulic chamber toprevent leakage to the environment. The method further includes placinga top portion of the annular BOP onto the body. The top portion includesa cap, an elastomeric element, and a piston. The cap couples with thebody to form the housing and enclose the elastomeric element and pistoninside of the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present technology can be better understood on reading the followingdetailed description of nonlimiting embodiments thereof, and onexamining the accompanying drawings, in which:

FIG. 1 is a perspective view of a subsea BOP assembly.

FIG. 2 is a perspective view of a lower marine riser package.

FIG. 3 is a part exterior part cross-sectional view of an annular BOPaccording to an embodiment of the present disclosure.

FIG. 4 is a bottom view of a base of the annular BOP according to anembodiment of the present disclosure.

FIG. 5 is a detailed view of a connection between the annular BOP andeither a ram BOP or another subsea equipment according to an embodimentof the present disclosure.

FIG. 6 is a partially exploded view of the annular BOP according to anembodiment of the present disclosure.

FIG. 7 is a partially exploded view of an annular BOP, according to anembodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The foregoing aspects, features, and advantages of the presenttechnology can be further appreciated when considered with reference tothe following description of preferred embodiments and accompanyingdrawings, wherein like reference numerals represent like elements. Thefollowing is directed to various exemplary embodiments of thedisclosure. The embodiments disclosed should not be interpreted, orotherwise used, as limiting the scope of the disclosure, including theclaims. In addition, those having ordinary skill in the art canappreciate that the following description has broad application, and thediscussion of any embodiment is meant only to be exemplary of thatembodiment, and not intended to suggest that the scope of thedisclosure, including the claims, is limited to that embodiment.

Referring to FIG. 1, a prior art subsea riser assembly includes ablowout preventer (BOP) stack 11 that connects to a subsea wellheadhousing (not shown) at the upper end of a well being drilled. Theassembly also includes a lower marine riser package (LMRP) 13 thatconnects to the upper end of BOP stack 11. BOP stack 11 has a number ofram preventers 15 for selectively closing the passage through BOP stack11. Some of the ram preventers 15 will close around a string of pipe(not shown) extending through BOP stack 11. At least one other rampreventer 15 will shear the string of pipe and close the passage.

FIGS. 1 and 2 are schematic illustrations, and LMRP 13 as shown in FIG.2 appears slightly different; however, for the purposes concernedherein, they are equivalent. Referring also to FIG. 2, LMRP 13 issecured to a lower end of a riser 17 that extends up to a floatingvessel or drilling platform at the sea surface. Riser 17 has a centralmain conduit through which strings of pipe are lowered into the well.Riser 17 also has auxiliary lines that connect to choke and kill lines19 for circulating fluid to and from the BOP stack 11 below rampreventers 15. LMRP 13 has also control pods 21 supplied with hydraulicfluid pressure and/or electrical signals for controlling variouscomponents of LMRP 13 and BOP stack 11. LMRP 13 has one or more annularBOPs 23 (only one shown) that will close around pipe of a variety ofsizes and also fully close in the event a pipe string is not extendingthrough LMRP 13. A flex joint 25 connects an upper portion of LMRP 13 toriser 17. The lower of annular BOP 23 connects to a connector 27 whichconnects LMRP 13 to the upper end of BOP stack 11. In some embodiments,in the event of an emergency and for maintenance reasons, a signal maybe sent to control pod 21 to cause connector 27 to disconnect from BOPstack 11. For a surface stack the annular is connected to the upper ramBOP.

FIG. 3 is a part exterior, part cross-sectional view of an annular BOP29 according to an embodiment of the present disclosure. Annular BOP 29has an annular housing 31 that is a generally tubular in shape. Annularhousing 31 has a longitudinal axis 33 that passes concentrically througha central cavity 35. An annular piston 37 is axially movable in centralcavity 35 in response to hydraulic fluid pressure applied to centralcavity 35 above and/or below annular piston 37. An upper end portion ofannular piston 37 engages an elastomeric element 41, which has a centralpassage through which a string of pipe (not shown) can be positioned. Insome embodiments, upward movement of annular piston 37 deformselastomeric element 41, causing the elastomeric element to constrictradially inward and thus constrict the central passage to seal around astring of pipe. If no pipe is present, the central passage will fullyclose.

In some embodiments, the annular housing 31 is comprised of a body 43and a cap 45, in which the body 43 forms a bottom portion of the annularhousing 31 and the cap 45 forms a top portion of the annular housing 31.The body 43 and the cap 45 are secured to each other to form the annularhousing 31 and contain the piston 37 and the elastomeric element 41. Insome embodiments, the cap 45 secures to the body 43 with a lockingmember 47. Cap 45 has a concentric upper opening 49 with a diameter thesame or smaller than the diameter of central passage of the elastomericelement 41 when the elastomeric element 41 is not being deformed. Aconcentric lower opening 51 is located at a lower end of the body 43 andis the same or smaller diameter as upper opening 49.

The body 43 includes a connector base 39 located at the bottom of theannular BOP 29 and configured to connect the annular BOP 29 to anotherpiece of equipment, such as a ram BOP or connector 27 (FIG. 2). Adetailed view of a connection region 50 of the annular BOP 29 is shownin FIG. 4. FIG. 5 is a bottom view of the connector base 39. Referringto FIGS. 3 and 4, the connector base 39 has a plurality of fastenerholes 53 formed therethrough. Specifically, the fastener holes extendfrom an interior of the annular BOP 29 or housing 31 to an exterior ofthe annular BOP 29 or housing 31. The fastener holes 53 allow fasteners55 (e.g., bolts, studs, screws, etc.) to be placed therein and securethe annular BOP 29 to another piece of equipment below the annular BOP29. FIG. 4 is a detailed view of a connection region 50 of the annularBOP 29 according to an embodiment of the present disclosure. Referringto FIGS. 3 and 4, specifically, the fasteners 55 extend from inside theannular BOP 29 to outside the annular BOP 29 beneath the annular BOP 29where the fasteners 55 secure to another piece of equipment. Asillustrated, the other piece of equipment may be positioned directlyadjacent (i.e., beneath) the base 39 of the annular BOP. The fasteners55 extend through the base 39 and directed into the other piece ofequipment 73 (FIG. 7), securing the annular BOP 29 and the other pieceof equipment. In some embodiments, stud nuts 65 (or the like) may beapplied to the fasteners 55 to secure the fasteners 55.

Referring still to FIGS. 3 and 4, the annular BOP further includes aseal plate 57 positioned at least partially adjacent interior ends ofthe plurality of fasteners. The seal plate 57 is also circular andconcentric with the rest of the annular BOP 29. In some embodiments, theseal plate 57 extends across the entire area above the plurality offasteners. Additionally, a first seal 59 is positioned circumferentiallyaround the seal plate 57 and seals between the seal plate 57 and aninterior surface 61 of the housing 31. In some embodiments, a seal 69 ispositioned at an inner diameter 63 of the seal plate 57 and sealsbetween the seal plate 57 and a piston sleeve 64. In some embodiments, aseal 72 is positioned beneath the piston sleeve 64 and seals between thepiston sleeve 64 and the base 39. In some embodiments, a combination ofsuch seals may be used to seal the fastener holes 53 off from the restof the annular BOP 29.

A recessed chamber 67 is formed adjacent the fastener holes 53 toaccommodate the fasteners 55 and stud nuts 65, and allows for sealingthe region from the rest of annular BOP 29. Specifically, the recessedchamber 67 is sealed by the seal plate 57 and the first and second seals59, 69. In some embodiments, a vent port 71 is formed in the housing 31and communicatively couples the recessed chamber 67 to outside of thehousing annular BOP 29. This allows for any leaks in the recessedchamber 67 to be detected, such as from wellbore fluids that may havemoved past the piston sleeve seal 72 and/or hydraulic closing chamberseals 59 and 69. FIG. 6 illustrates another embodiment of an annular BOP29. As illustrated, in some embodiments, the seal plate 57 may beintegrated with the piston sleeve 64. That is, the seal plate 57 and thepiston sleeve 64 are formed as one body.

FIG. 7 is a partially exploded view of the annular BOP 29 according toan embodiment of the present disclosure. Because the fasteners 55 extendfrom within the housing of the annular BOP 29, the fasteners 55 areaccessed from inside the annular BOP 29. Thus, the connection to anotherequipment 73 is made before the entire annular BOP 29 is assembled. FIG.6 shows the assembling of the annular BOP 29 when connecting to anotherequipment 73. The body 43 (i.e., base 39) of the annular BOP 29 is firstplaced onto another equipment 73 and secured to the other equipment 73via the fasteners 55, which traverse the base 39 of the annular BOP 29and extends into the other equipment 73. In some embodiments, stud nuts(or the like) are secured to the ends of the fasteners 55 at the annularBOP side. Thus, the body 43 of the BOP 29 is securely coupled to theother equipment 73. The rest of the annular BOP 29 can then beassembled. In some embodiments, the piston 37, the elastomeric element41, and the cap 45 may then be lowered/placed onto the body 43. The cap45 locks into place with the body 43 to form the housing and contain thepiston 37 and elastomeric element 41 therein. The entire annular BOP 29is thereby connected to the other equipment 73. The other equipment maybe any suitable piece of equipment that may be connected to an annularBOP, such as but not limited to a connector, or a spacer spool.

The annular BOP 29 of the present disclosure provides a way to create aconnect between the annular BOP 29 and a ram BOP or a connector on asubsea stack to connect to the BOP stack 11 without the need for aconnection flange, which is how the connection is conventionally made.The connection flange adds additional height and weight to the annularBOP 29. Thus, the present annular BOP 29 which is connectable directlyfrom the base of the housing does not require the flange and thus can beshorter overall.

While the present disclosure has been described with respect to alimited number of embodiments, those skilled in the art, having benefitof this disclosure, can appreciate that other embodiments may be devisedwhich do not depart from the scope of the disclosure as describedherein. Accordingly, the scope of the disclosure should be limited onlyby the attached claims.

What is claimed is:
 1. An annular blowout preventer (BOP), comprising:an annular housing having a connector base, the connector basecomprising a plurality of fasteners extending from an interior of thehousing to an exterior of the housing via fastener holes formed throughthe connector base; a seal plate positioned at least partially adjacentinterior ends of the plurality of fasteners to seal against the fastenerholes; an annular elastomeric element positioned within the interior ofthe housing; and an annular piston positioned within the interior of thehousing, wherein the piston, when driven towards the elastomericelement, deforms the elastomeric element and forces the elastomericelement to constrict radially inward.
 2. The annular BOP of claim 1,further comprising: a seal positioned circumferentially around the sealplate between the seal plate and an interior surface of the housing. 3.The annular BOP of claim 1, further comprising: a seal positioned at aninner diameter of the seal plate.
 4. The annular BOP of claim 1, furthercomprising: a plurality of stud nuts or bolts located within theinterior of the housing and securing the plurality of studs or bolts,respectively.
 5. The annular BOP of claim 1, wherein the housing furtherincludes a recessed chamber adjacent fastener holes, the recessedchamber sealed by the seal plate, and wherein a vent port formed in thehousing communicatively couples the recessed chamber to outside of thehousing.
 6. The annular BOP of claim 1, wherein the plurality offasteners are configured to couple to another component positionedadjacent the annular BOP.
 7. The annular BOP of claim 6, wherein theother equipment is a ram BOP, spool, or connector.
 8. The annular BOP ofclaim 1, wherein the housing comprises a body forming a bottom portionof the housing and a cap forming a top portion of the housing.
 9. Asubsea system, comprising: a riser coupled to a vessel; a lower marineriser package coupled to the riser opposite the vessel; an annularblowout preventer (BOP) coupled to the lower marine riser package, theBOP comprising: an annular housing having a base, the base comprising: aplurality of fasteners extending from an interior of the housing to anexterior of the housing via fastener holes formed through the base; aseal plate positioned at least partially adjacent interior ends of theplurality of fasteners; and an annular elastomeric element positionedwithin the interior of the housing; and an annular piston positionedwithin the interior of the housing, wherein the piston, when driventowards the elastomeric element, deforms the elastomeric element andforces the elastomeric element to constrict radially inward; and one ormore ram BOPs coupled to the annular BOP.
 10. The annular BOP of claim1, further comprising: a seal positioned circumferentially around theseal plate between the seal plate and an interior surface of thehousing.
 11. The annular BOP of claim 1, further comprising: a sealpositioned at an inner diameter of the seal plate.
 12. The annular BOPof claim 1, further comprising: a seal positioned at an interior surfaceof the base.
 13. The annular BOP of claim 1, wherein the housing furtherincludes a recessed chamber adjacent the fastener holes, the recessedchamber sealed by the seal plate, and wherein a vent port formed in thehousing communicatively couples the recessed chamber to outside of thehousing.
 14. The annular BOP of claim 1, wherein the plurality offasteners include at least one of studs, bolts, or screws.
 15. A methodof installing an annular blowout preventer (BOP), comprising: placing abody of a housing of the annular BOP onto a piece of equipment, whereinthe body has a base with a plurality of fastener holes formedtherethrough; securing the body to the equipment with a plurality offasteners inserted through the plurality of fastener holes; and placinga top portion of the annular BOP onto the body, wherein the top portionincludes a cap, an elastomeric element, and a piston, wherein the capcouples with the body to form the housing and enclose the elastomericelement and piston inside of the housing.
 16. The method of claim 15,wherein the equipment is a ram BOP, a connector, or a spacer spool. 17.The method of claim 15, further comprising: forming a seal between thefastener holes and a main cavity of the annular BOP via a seal plate, afirst seal on an outer perimeter of the seal plate, and a second seal onan inner perimeter of the seal plate.
 18. The method of claim 15,further comprising: forming a seal between the fastener holes and a maincavity of the annular BOP via a piston sleeve with a first seal on anouter perimeter and a second seal on a bottom face of the piston sleeve.19. The method of claim 18, wherein the housing further includes arecessed chamber adjacent fastener holes, the recessed chamber sealed bythe seal plate or the piston sleeve.
 20. The method of claim 15, whereinthe housing further comprises a vent port for leakage detection.